Local faults, like spalls in rolling element bearings, give rise to periodic impulsive excitation to the supporting structure. So, an impact based force evaluation, the resulting response analysis of the structure, and experiments are reported in this paper to identify local bearing fault as well as its size. Magnitude and duration of such excitation force are functions of bearing geometry, load, speed, and size of defect. An approach based on the principles of engineering mechanics is followed to obtain a time function of the impact force which is used next to simulate the response of the bearing housing. This response is analyzed in time and frequency domains to get an idea about the bearing fault and its size. Experiments conducted on deep groove ball bearing for different defect sizes and different speeds show acceptable correlation with the theoretical simulation. Hence, the impact based model has laid a theoretical platform to gain insight into the physical phenomena, which is not measured in practice, through impact excitation mechanism and may hold sufficient potential for bearing fault identification.